From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C930EC43219 for ; Fri, 3 May 2019 10:21:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A34D22075E for ; Fri, 3 May 2019 10:21:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727179AbfECKVd (ORCPT ); Fri, 3 May 2019 06:21:33 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:57940 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726289AbfECKVd (ORCPT ); Fri, 3 May 2019 06:21:33 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9D2FA374; Fri, 3 May 2019 03:21:32 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 351383F557; Fri, 3 May 2019 03:21:31 -0700 (PDT) Date: Fri, 3 May 2019 11:21:28 +0100 From: Mark Rutland To: Sami Tolvanen Cc: Catalin Marinas , Will Deacon , Kees Cook , Nick Desaulniers , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] arm64: use the correct function type in SYSCALL_DEFINE0 Message-ID: <20190503102128.GD47811@lakrids.cambridge.arm.com> References: <20190501200451.255615-1-samitolvanen@google.com> <20190501200451.255615-3-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190501200451.255615-3-samitolvanen@google.com> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 01, 2019 at 01:04:51PM -0700, Sami Tolvanen wrote: > Although a syscall defined using SYSCALL_DEFINE0 doesn't accept > parameters, use the correct function type to avoid indirect call > type mismatches with Control-Flow Integrity checking. Generally, this makes sense, but I'm not sure that this is complete. IIUC this introduces a new type mismatch with sys_ni_syscall() in some cases. We probably need that to use SYSCALL_DEFINE0(), and maybe have a ksys_ni_syscall() for in-kernel wrappers. Thanks, Mark. > > Signed-off-by: Sami Tolvanen > --- > arch/arm64/include/asm/syscall_wrapper.h | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h > index a4477e515b798..507d0ee6bc690 100644 > --- a/arch/arm64/include/asm/syscall_wrapper.h > +++ b/arch/arm64/include/asm/syscall_wrapper.h > @@ -30,10 +30,10 @@ > } \ > static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) > > -#define COMPAT_SYSCALL_DEFINE0(sname) \ > - asmlinkage long __arm64_compat_sys_##sname(void); \ > - ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO); \ > - asmlinkage long __arm64_compat_sys_##sname(void) > +#define COMPAT_SYSCALL_DEFINE0(sname) \ > + asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused); \ > + ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO); \ > + asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused) > > #define COND_SYSCALL_COMPAT(name) \ > cond_syscall(__arm64_compat_sys_##name); > @@ -62,11 +62,11 @@ > static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) > > #ifndef SYSCALL_DEFINE0 > -#define SYSCALL_DEFINE0(sname) \ > - SYSCALL_METADATA(_##sname, 0); \ > - asmlinkage long __arm64_sys_##sname(void); \ > - ALLOW_ERROR_INJECTION(__arm64_sys_##sname, ERRNO); \ > - asmlinkage long __arm64_sys_##sname(void) > +#define SYSCALL_DEFINE0(sname) \ > + SYSCALL_METADATA(_##sname, 0); \ > + asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused); \ > + ALLOW_ERROR_INJECTION(__arm64_sys_##sname, ERRNO); \ > + asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused) > #endif > > #ifndef COND_SYSCALL > -- > 2.21.0.593.g511ec345e18-goog >